Kinetic study of retro-aldol condensation of glucose to glycolaldehyde with ammonium metatungstate as the catalyst



The kinetics of the retro-aldol condensation of glucose to glycolaldehyde was studied in a batch reactor at 423–453 K using ammonium metatungstate (AMT) as the catalyst. Three consecutive reactions were considered: retro-aldol condensation of glucose to erythrose and glycolaldehyde (R1), retro-aldol condensation of erythrose to two moles of glycolaldehyde (R2), and further conversion of glycolaldehyde to side products (R3). Fitting of the experimental data showed that R1 was first-order reaction while R2 and R3 were 1.7th- and 2.5th-order reaction, respectively. Conversely, the reaction rate of R1 was 0.257th-order dependence on the concentration of AMT catalyst. The apparent activation energies for R1, R2, and R3 were 141.3, 79.9, and 52.7 kJ/mol, respectively. The high activation energy of R1 suggests that a high temperature is favorable to the formation of glycolaldehyde. The experimental C–t curves at different temperatures and initial glucose concentrations were well predicted by the kinetic model. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3804–3813, 2014